Miami Beach Mayor Philip Levine recently went on a Facebook rant against Airbnb.
A potential Democratic candidate for governor in 2018, Levine wrote that Miami Beach commissioners aren't the only opponents of the company, which allows property owners to rent houses and apartments, or a bedroom, to visitors across the world. He said officials in New York, San Francisco and Miami also don't support Airbnb.
"Because it destroys neighborhoods, buildings, decreases real estate values and increases costs for workforce housing!!!!!" he wrote.
We decided to tackle two of Levine's attacks: that Airbnb decreases real estate values and increases costs for workforce housing. (By workforce housing, Levine was referring to homes for people who earn 60 to 120 percent of an area's median income.)
Several factors influence housing costs, even in areas with Airbnb and where rents are rising.
Jack McCabe, a South Florida real estate analyst, said it's premature to make broad claims about the impact of Airbnb.
"It's still too soon to really have data for a long enough period of time to make these types of assumptions or assertions," he said.
Some real estate experts said Airbnb is the latest scapegoat for the lack of available affordable rentals — a problem that predated the company.
Definitive, independent analysis about the impact of Airbnb is generally lacking.
Most of the research we found focused on one city, or ones that were already plagued by housing crunches.
For example, a San Francisco official said that "illegitimate rentals" took 1,900 long-term housing units off the market, but it isn't clear how many of those were affordable for people earning median incomes or less.
Levine sent us multiple articles about the impact of Airbnb on housing.
A 2015 study by the Los Angeles Alliance for a New Economy, an advocacy group for working families, concluded Airbnb was exacerbating the lack of affordable rental units in Los Angeles. The group also did a 2014 study that found rents were growing faster in Los Angeles neighborhoods with the highest Airbnb listing density.
Roy Samaan, the author of the studies, told PolitiFact that he couldn't definitively say that Airbnb was the cause of rents increasing. Several factors influence rental costs.
Since Airbnb doesn't make its booking information fully public, it's difficult to fully assess the impact.
Another piece of evidence Levine cited stemmed from a report commissioned by affordable-housing activists in New York City. It concluded that short-term rentals are reducing the vacancy rate, which causes increases in rental prices.
The study zeroed in on a subset of about 8,000 Airbnb listings in New York City and concluded if those units were put back on the regular market, the vacancy rate would rise from the current 3.4-3.6 percent to 4 percent.
Richard K. Green, a real estate professor at the University of Southern California, told PolitiFact those 8,000 units would be absorbed quickly in a rental market of more than 2.2 million units.
"I am skeptical that the local vacancy rates would move as much as the authors of the New York study would suggest," he said.
Now Airbnb argued through its own packet of articles and studies that its listings don't hurt real estate values or supply.
A FiveThirtyEight analysis concluded that "Airbnb's impact is probably still small in most cities," although it could grow. The statistics-based news website used Airbnb booking and revenue data to examine how many units Airbnb could be taking off the rental market nationwide.
Stockton Williams, executive director of the Terwilliger Center for Housing at the Urban Land Institute, told FiveThirtyEight that the Airbnb units don't add up to much as a percentage of total rental units in big cities in the United States.
Other factors, such as the increasing demand for urban living, have played a much larger role in driving up prices in big cities, he said.
"There is a considerable amount of anecdotal evidence that they may be occurring in a relatively small number of individual neighborhoods and properties — and therefore quite real to affected residents and owners," Williams told us.
Murray Cox, owner of Inside Airbnb, a website that analyzes data about Airbnb listings, told Business Insider that Airbnb can't entirely be blamed for housing issues in cities that were already expensive.
Green, the real estate professor at the University of Southern California, said that focusing on Airbnb doesn't get to the heart of the matter — "that cities are making it more and more difficult to build housing."
We rate this claim Mostly False.
Edited for print. Read the full version at PolitiFact.com/florida.